Telephone-exchange system.



- c w. KECKLER. TELEPHONE EXCHANGE SYSTEM. AFPLIQATION FILED APR.26, 1917 15258,,782. Patent e d Mar. 12, 1918.

WEnn saa'rns manna onnrcn.

CHARLES W. KECKLER, or NEWARK, NEW annsnxnssreivon TO WESTERN ELECTRIC:

COMPANY, INCORPORATED, on NEW YonK, n. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent. Patented Mar, 12 1918;

Application filed April 26, 1917. Serial No. 164,636.

To all whom it may concern:

Be it known that 1, CHARLES W. KECKLER, a citizen of the United States, residing at Newark, in the. county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone-EX- change Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems which employautomatic ringing for signaling purposes, and which are provided with trunk lines extending to private branch exchanges, chief operators" desks and like positions. r

The object of this invention is to prevent the usual objectionable and disagreeable click in the answering operators receiver when a call over the trunk to which a source of ringing current is connected is being answered. i

In accordance'with a feature of this invention, when an'operator answers the call, by actuating a listening key,contacts thereof cooperate to directly disable the receiver of an operators telephone set during the period in which ringing current is being removed, after which a relay isoperated to render the receiver operative; r This invention is illustrated in the accompanying drawing in which all apparatus is shown in its normal and unactuated condition.

There is shown in the drawing a telephone exchange system containing oneembodiment ofthis invention, and comprising a cord circuit A, located at one section C of a switchboard, and a trunk circuit B extending from this section G to a desk-operators position D at which there is a signaling device, a listoning key and an, operators telephone set.

It is believed that this invention will be fully understood from a description of the operation of the system shown in the drawing, audit will be so described;

The operator'at section C, desiring to signal -the desk operator D, inserts a plug 5 into a jack 6, whereupon lamp 7 will be lighted and relay 8 operated. The operation of relay 8 causes the actuation of a ringing relay 9'over a circuit from battery through resistance 10, winding of ringing relay 9, normal contact of relay 11, contact of tripping relay 12, and the closed contact of relay 8 to ground. The operation of ringing relay 9 connects a source of ringing current 15 to the trunk circuit B, causing the operation of relay 16 over aicircuit from the source of ringing current 15 through the winding of tripping relay 12, lower alternate contact of ringing relay 9, ring contacts of the plug 5 andthe j ack6, condenser 17, right-hand winding of relay 16, tip contacts of thejack 6 and plug 5, and the upper alternate contactof ringing relay 9 to ground. The operating winding of relay 16 is of high impedance, so that .thetripping relay 12 is not actuatedwhen in circuit therewith. Relay 16, upon being energized, attracts its armature and locks up over a circuit'from battery through the lefthand winding and contact thereof, and contact 4a of listening key 18 to ground. Upon. the actuationof relay 16, lamp 19 is lighted to furnish a signal to the desk operator, and remains lighted until the desk operator actuates listening key 18.. The'ringing current also remains connected to the trunk circuit until the actuation of thejlistem'ng key "by the desk operator. t

The desk operator, upon observing the lighted condition of lamp 19, actuates listening key l8,'causing the following operations in the order named: i V

1. Opens contact 4: in the locking circuit of relay 16, causing the release thereof and the effacement of lamp 19.

2. The closure of contact 27,thereby' establishinga short-circuit for the receiver 29 of the answering opera-tors telephone set which short circuit also includes the nor; nially closed contact 30 of a relay 31. i

3. The closure of contacts 32 and 33 connecting the operators telephone set to and bridging relay 34 across, the tip and ring conductors of the trunk circuit. Tripping relay 12 in the cord circuit A, and relay 34:, which isslow operating, thereupon operate; The operation of tripping relay 12 permits the operation of relay 11, whichin turn short-circuits and causes the release of ring ing relay 9. By this time relay 34 had attracted its armature, bridging relay 31 across the tip and ring conductors of the trunk. circuit so that'by the'time ringing relay 9 has fully released itsarmatures,

substituting current from the battery in the 1 cord circuit for the ringing current, an ener-' peating coil 36, Winding of supervisory relay the jack 6 and plug 5, upper normal contact of ringing relay 9, and Winding 38 of repeating coil 36 to ground. Relay 31, upon attracting its armatures, completes a lockingcircuit for .itselhwhich includes contact.

39, opens contact 30,.vvl1iclrisinthe short circuiting path of the receiver 29, and opens contact 40, disconnecting relay ,34sfrom the trunk circuit.

Since the supervisory relay 3,7-is incit cuitwith therelayv .31, it operates'and places the resistance 10 .in' parallel With the lamp 7,- whic'h is thereby etface'd, indicating to the operator at the section or position G that the. desk operator D has answered. Relay 34 is also slow releasing, so that during the timethatringing relay 9. is releasing its armatures When for. an instant no current is connected to the trunkcircuit, the contact ofrelay 3 lwillbe maintained closed until battery is connected with the trunk. Relay 31-, which remains in bridge with the talking conductors of the trunk circuit after. ringe ing current hasbeentrippe-zl, serves an impedance and holding coil forms hing thesupervisory relay 37 operated.

From thcabove description it Will readily be seen that the system embodying the present invention permits of; the tripping. of ringing current and 1 the connection of talkingcurrent to the trunkcircuit ,While the operators receiver is entirely outof the circuit, thereby. avoiding in the answering operators receiver the disagreeable clicks usually attending the operation of tripping the ringing current. Since the listening key contact itself establishes the short circuit for the receiver 29, close, margins which have been present in circuits of. a similar nature heretotore'employcd are avoided.

What is claimed is:

1. A telephone exchange system comprising a trunkcircuit extending from one telephone switchboard to a second board, means at onelofsaid boards for applying ringing currentover the trunkto the other board, an operators telephone set at; said other board, a switch thereatactuatediby the operator for connecting .the operators telephone setlto the trunkcircuit and for disconnecting. the ringing current from the trunk, contacts of .thesivitch included in the talking, circuit of the trunk andengaged upon, the actuation thereof i to Short-circuit the receiver. of he operatorstelephone set, and means operating. after t th a 1 f ringingcurrent to remove the shortcircuit fromthe receiver. 7

2.' A telephone exchange system comprise ing a trunk circuit extending from one telephone switchboard to a second board, means atone. of said boards for applying ringing current over the trunk to the other board, anoperators telephone setat said other board, a switch thereat actuated by the operator for connecting the operators telephone set to the trunk circuit and for disconnecting the ringing current from the trunk, a short circuit for the receiver of the operators telephone, set established upon the actuation of theswitch;- and including contacts thereof, and nea-ns operatingafter the removal of ringing current to v remove the short circuit from the receiver.

A telephone exchange systenrcoinprisinga trunk circuit extending from one telephone switchboard to a second board, means at one of said boards for applying ringing current, over the trunk to. the other board,

an operatofls telephone set. at said other.

board, ttSWltCll thereat actuated bythe operatoryfor. connecting the operatolfzstelee phoneset to the tr circuit andior disconnecting tiie ringing current from the trunk, contacts ot the switch included in the talking circuit of the trunk and engaged upon the actuation thereof to short circuit the receiver oftheoperators telfibl one set, and a relay operating after the removalcf ringing current to remove thesholitcircuit from the receiver.

-,A., le1 10nc e che e' y te compri ing a trunk circuit extending from one teleph nesw t bo rd a econ bo dam a s at one ofsaid boards for applying ringing current overthe, trunk to the other board,

an operators, telephone, set at said, other} board, a sivltchthereat; actuated by the operator for. connecting the operators telephone. set to the trunk circuit and for is connecting the ringing, current/from, the

trunk, a short circuit for the receiver of the.

operatorls telephoneset establishednpon, the actuatlon 0t the switch and including con;

tacts thereon and a, relay v operating, afterv the removal of r ng ng current to removethe.

short circuit from the receiver.

5. A. telephone exchange system compr1 s-.

ing a trunk; circuit extendinglrom one teleg phone switchboard to a second board, means at n seid bo f r rp yineri g s current over the trunk to the other board,-

an operatorstelephone set. at said other board, a svvitclrthereat actuated by th e operator for connecting. the operatoristelephone set to tlietrunk circuit andfor dis; connecting the ringihgrurrentl from the trunk. a" short circuiting path for there-1 e ver 1. t rerat ri l el phone t t lished uponv the actuation, of the switch: and including. a normallyflclosed contact, and means operating after the e rnpyal of ,ring, ing current to" open" the normally closed .con tact.v

A telephone exchange system comprising a trunk circuit extending from one teleceiver of the operators telephone set estab-v lished upon the actuation of the switch, and a relayhaving a normally closed contact in the short-circuiting path energized after removal of ringing current.

7. A telephone exchange system comprising a trunk circuit extending from one telephone switchboard to a. second board, means at one of said boards for applying ringing current over the trunk to the other board, an

operators telephone set at said other board, a switch thereat actuated by the operator for connecting the operators telephone set to the trunk circuit and for disconnecting the ringing current from the trunk, a source of direct current connected with the trunk circuit Copies of this patent may be obtained for upon the disconnection of ringing current therefrom, a disabling circuit for the re-. ceiver of the operators telephone set established upon the actuation of the switch, a

relay energized over a circuit including the source of direct current, and a normally closed contact in the disabling circuit opened upon the energization of the relay.

8. A telephone exchange system comprising a trunk circuit extending from one telephone switchboard to a second board, means at one of said boards for applying ringing current over'the trunk to the other board, a switch at the other board, a relay bridged across the trunk circuit by the actuation of the switch for disconnecting the ringing current from the trunk, an operators telephone set connected with the trunk and the receiver thereof disabled by the actuation of the switch, and a second relay connected with the trunk upon the operation of the first relay and energized thereover after:

ringing current is removed to render the re-s celver operative.

In witness whereof, I hereunto subscribe my name this 25th day of April A. D., 1917."

. CHARLES W.YKEOKLER.

five cents each, by addressing the Commissioner of Patents,

Washington, D. 6. a I 

